1. Field of the Invention
The present invention relates to ultracentrifuge rotors and, more particularly, to a method and apparatus for increasing the speed and improving the "g" force operation of ultracentrifuge rotors.
2. Description of the Prior Art
Ultracentrifuge rotors are limited to a degree of centrifugal force at which they break down and disintegrate because of the high "g" forces. Therefore, in selecting materials for use in constructing ultracentrifuge rotors, important properties are high strength, high modulus, and low density. The strength-to-density ratio is important because the weight of the rotor itself contributes significantly to the stress forces thereon during operation. Common materials having relatively high strength-to-density ratios are aluminum, titanium, and heat treated steel.
It is also known to use filament windings of high strength, high modulus fibers, such as boron or carbon, in ring form, to strengthen and stiffen rotor structures and improve their performance. The ability of these fiber rings to support the tangential stresses is directly related to the filament density. To be useful for practical rotor designs, high filament density rings of thicknesses of 1/4" and greater are needed. Furthermore, design analysis has shown that the tangential stresses increase from the inside to the outside diameter of such supporting rings. However, with fine fibers, it is difficult to maintain a consistent winding pattern for more than ten to twelve layers of fibers. As a result, rings used heretofore have a relatively high filament density at the inside diameter of the ring but a relatively low filament density at the outside diameter of the ring. The low filament density results in a lower specific modulus and strength as the ring thickness increases and this is opposite from the desired strength and modulus distribution.